Physics: Wave Interference and Laser Diffracrtion

As long as waves have the same wavelength

they interfere (interact) constructively and destructively in a specific pattern

wave interference pattern

haracterized by light and dark bands

Light bands

result of constructive interference,

dark bands

result of destructive interference

Young

double-slit experiment to exhibit the interference of light waves.

light is a wave

Mini Ripple Tank

small pan for water and a vibrating source

Strobe light

projects waves of various frequencies on a fold-down screen.

Mini Ripple Tank Directions

1. Fill acrylic bath with water, ~½ way

2. Add a single wave attachment to vibrator. Turn waves on and wave frequency to

mid-range

3. Close the lid and adjust strobe frequency till you see a wave pattern. Take a picture for

your assignment

4. Repeat 2-3 for double wave attachment

5. Using different attachments and accessories create your own wave interference pattern

Synchronizing mode

links wave frequency and strobe to measure wwavelength

Double-slit diffraction definition

experiment where light is permitted to diffract through slits that produce fringes or wave like interference patterns on an opposite screen

observed outcome where light passing through two slits produces beams that interact with each other.

Intereference Pattern and equation

explains phenomena with light passing through double slits

Condition for constructive intereference

σ=nλ

σ

pass difference between r1 and r2

d*sin θ

λ

wavelength of light

QOP traingle

sin θ~ tan θ=x/L

Relationship between max position on screen, slit, and light wavelength

x/L=nλ/d → x=(λ*L) *1/d

What does a smaller distance between slits result in?

large fringe seperation

inverse relationship or so-called recipocal lattice